Electrical current testing



March 9, 1937. G. B. STANTON ELECTRICAL CURRENT TBS TING INSTRUMENT Original Filed Aug. 24, 1931 2 Sheets-Sheet l Inventor G s'oeat 545/4 fi/vrm Allorney March 9, 1937. STANTON Re. 20,290

ELECTRICAL CURRENT TESTING INSTRUMENT A llomey 8, Egg,- a7

Reis'cued mam-9,1937 I UNITHED STATE Re. i

ELECTRICAL CURRENT TESTING INSTRUMENT George B. Stanton, Brooklyn, N. Y.

Original No. 1,912,800, dated June s, 1933, Serial No. 559,066, August 24, 1931. Application for reissue October 9, 1933, Serial No. 692,91; 7

9 Claims.

The present invention relates to new and useiul improvements in electrical instruments, and more particularly it pertains to an electrical instrument for measuring electric current.

tion to provide a measuring instrument which will measure current of either direct or alternating type. I

A further object of the invention resides 'in a novel construction which particularly'adapts -the instrument for use in the testing of overhead or underground cables or similar conducnovel construction whereby the indicating means is adjustably and removably associated with a magnetic element by which it is operated.

With the above and other objects in view, reference will be had to the accompanying drawings wherein;

Figure 1 is a view in front elevation partly in section illustrating a device constructed in accordance with the present invention,

Figure 2 is a side elevation thereof,

Figure 3 is a vertical sectional view taken on the line 3-3 of Figure 2,

Figure 4 is a sectional view taken on the line 4-4 of Figure 3, and a Figure 5 is a top plan view partly in sectio taken on line 5-5 oi! Figure 1. 7

Referring more particularly to the drawings,

the device comprises a magnetic member Iii which comprises two portions A and B. Each of the portions A and B is formed of a plurality of separate plates of transformer steel and each may be either rectangular or circular in cross section. The two portions A and B are pivotally-connected together as at Ii, and a suitable ball or the like I! may be employed at this point.

By this construction, the two portions A and B are movable relatively to each other thus providlng for their introduction over a cable of any desired size.

Each of the portions A and B is formed with a pole or terminal i3, and as illustrated in the 66 drawings, these poles have slightly tapered por- It is one of the primary objects of the inventions at the ends to increase the flux density in the gaps between the poles and it will also be noted, that the faces of the poles are curved as Y and for a purpose to be hereinafter described.

The reference character It designates a cable or electrical conductor carrying a current, and it is the current of this cable that is to be measured by the instrument herein shown. In carrying out the operation, the magnetic member In .l

is adapted to surround the cable and means is provided to hold or support the same upon the cable I6. In the present embodiment of the invention, this means consists of two curved members I! the shanks of which are slidably mounted as at l8 in brackets or the like 19 clamped by means of bolts or the like 20 upon the portions A and B of the magnetic member iii. Coil springs or the like 2i may be employed to maintain the members ll in engagement with the cable It.

An indicating means is provided and this indi-- cating means comprises a scale or the like 30 mounted within a suitable housing 3| which in turn is connected to the portions A and B of the magnetic member, in after the same has been adjusted in position upon the cable by means of clamps or the like comprising plates 33 and screws, bolts or the like 34.

This indicating means is bodily movable with respect to the magnetic member ii). Said indicating means carries a tubular extension 31 formed'of non-conducting material which is adapted for movable engagement and disengage ment in the gap between the poles H) of the mag- I netic member Hi.

this indicating means may be adjustably fixed with relation to the magnetic member l0, and in the present embodiment of the invention this means comprises recesses or the like '38 in the outer'side of the tubular member 31, said recesses 38 being connected by grooves 381:. Figures 2 and 4, and balls or similar pawl members 39 carried in tubes or the like 40 on the portions A and B and forced forwardly into engagement with the recesses 38 by means of springs or the like 4| the tension of which may be adjusted by screws or the like 42. j

The grooves 38:: alluded .to serve in practice to facilitate the guiding of the tubular member 31, and retain the same in proper position relatively to the pawl members 39.

Thus it will be apparent that the adjusted position of the indicating means depends entirely upon the recesses 38 in which the balls 39 are engaged.

Means is provided whereby The indicating mechanism includes a pointer 'or the like 40' which is carried by a shaft ll mounted in bearings 42'. This shaft ll carries a member H (see Figure which is preferably a'thin piece of iron or magnetic material and is influenced by the magnetic flux tending to complete the circuit between the poles i3 and thus.

more positions the two or more ranges of the' lower intensity, say three hundred amperes, by

introducing the tubular'member 31 a step further l within the gap of the pole pieces, the sensitiv'- ity of the instrument is increased because morecurrent transformers or shunts, and when a con, ductor under test carries both direct and alter nating currents my instrument is adapted to measure the sum of these currents simultaneously. I

From the foregoing it is apparent that the present invention provides a new and novel device of the aforementioned character which is current in the conductor can be accurately and expeditiously accomplished by a single person.

While the invention has been herein disclosed in a preferred form, it is to be understood that 1 the invention is not to be limited to the specific construction herein illustrated and that it may be practiced in other forms without departing from the spirit thereof.

Having thus described the invention. what I claim as new and desire to secure by Letters Patent of the United States, is:

I. An electrical measuring instrument comprising pivotallymounted magnetizable members having an air gap in the magnetic path thereof, an electrical indicating device having a tubular member being slidably supported in said air gap, and resilient means for supporting an electrical conductor at a predetermined position between the magnetizable members.

2. An electrical measuring instrument comprisingpivotally mounted magnetizable members having an air gap in the magnetic paththereoi, an electrical indicating device having a tubular portion being slidably supported in the air gap, means for maintaining said tubular member in predetermined positions in said air gap, and means for supporting an electrical conductor at a predetermined position between the magnetizable members and perpendicular to the magnetic path of said'mem'bers.

3. An electrical current testing instrument in for current measurements on either direct or ,al-; I 'ternating current circuits and without the aid 0 ture.

tions pivotally connected together, and resilient coacting clamping means carried by each of said portions for gripping engagement with an electricity conductor to support the instrument therefrom with the electricity conductor in spaced relation to said members.

4. An electrical current testing instrument including a magnetic member having spaced polepieces, means removably carried by the magnetic member for removably attaching the instrument to an electricity conductor, said means comprising a pair of oppositely disposed coacting spring actuated gripping elements, and indicating means adjustably mounted between the polepieces of the magnetic member.

5. An electrical current testing instrument comprising a magnetic member including a pair of pivotally connected portions, the free ends terminating in pole pieces, ooacting resilient clamping elements carried by said portions and extending inwardly 'toward each other being for clamping engagement with an electrical conductor.'to.=,be tested, an electrical indicating device,

'16. An electric current testing instrument comprising a magnetic member including a pair of pivotally, connected portions, the free ends termin'at ingin pole pieces, brackets carried by said s1 opposed clamping jaws slidably mountd'brackets, spring'means tending to urge leaf-[indicating device, and means for electrially connecting and supporting. said electrical device between the pole ends of said portions.

7. In an electric current testing instrument and in combination, a magnetic member having spacedl pole pieces, pawls carried by said memflber', and an indicating device having a tubular capable of attachment to cables or conductors of various sizes, and in which the measuring of the portion movable endwise between said pole pieces and pawls, said tubular portion having at spaced points in its length recesses to receive said pawls. and said indicating device also'having a' shaft turnable about its axis in said tubular portion.

amping jaws toward each other, an elec-' an armature in the tubular portion and on the shaft and movable with the shaft, a pointer on the shaft, a scale complementary to the pointer, and a spring co-operating with the shaft for returning the pointer to its initial position. 7

8. In an electric current testing instrument and in combination, a magnetic member having spaced pole-pieces, spring pressed balls carried by said member, and an indicating device having a ttmular portion movable endwise between said pole-pieces and balls and also having at spaced points in the length of said tubular portion recesses toreceive said spring pressed balls, and an armature, whereby the tubular portion and the armature .are retained in predetermined longitudinal spaced relation to the pole-pieces spaced pole-pieces, spring pressed balls carried: by said member, and an indicating device having a tubular portion movable endwise between said pole-pieces and balls and also having at spaced points in the length oi said portion recesses to receive'said balls and further having longitudinal grooves connecting said recesses and an arma- GEORGE B. STANTON. Y 

